| 1. |
- Thoma, B, et al.
(författare)
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An international, interprofessional investigation of the self-reported podcast listening habits of emergency clinicians: A METRIQ Study
- 2020
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Ingår i: CJEM. - : Springer Science and Business Media LLC. - 1481-8043 .- 1481-8035. ; 22:1, s. 112-117
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Tidskriftsartikel (refereegranskat)abstract
- ObjectivesPodcasts are increasingly being used for medical education. A deeper understanding of usage patterns would inform both producers and researchers of medical podcasts. We aimed to determine how and why podcasts are used by emergency medicine and critical care clinicians.MethodsAn international interprofessional sample (medical students, residents, physicians, nurses, physician assistants, and paramedics) was recruited through direct contact and a multimodal social media (Twitter and Facebook) campaign. Each participant completed a survey outlining how and why they utilize medical podcasts. Recruitment materials included an infographic and study website.Results390 participants from 33 countries and 4 professions (medicine, nursing, paramedicine, physician assistant) completed the survey. Participants most frequently listened to medical podcasts to review new literature (75.8%), learn core material (75.1%), and refresh memory (71.8%). The majority (62.6%) were aware of the ability to listen at increased speeds, but most (76.9%) listened at 1.0 x (normal) speed. All but 25 (6.4%) participants concurrently performed other tasks while listening. Driving (72.3%), exercising (39.7%), and completing chores (39.2%) were the most common. A minority of participants used active learning techniques such as pausing, rewinding, and replaying segments of the podcast. Very few listened to podcasts multiple times.ConclusionsAn international cohort of emergency clinicians use medical podcasts predominantly for learning. Their listening habits (rarely employing active learning strategies and frequently performing concurrent tasks) may not support this goal. Further exploration of the impact of these activities on learning from podcasts is warranted.
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| 2. |
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| 3. |
- van Rheenen, W, et al.
(författare)
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Common and rare variant association analyses in amyotrophic lateral sclerosis identify 15 risk loci with distinct genetic architectures and neuron-specific biology
- 2021
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 53:12, s. 1636-
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Tidskriftsartikel (refereegranskat)abstract
- Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease with a lifetime risk of one in 350 people and an unmet need for disease-modifying therapies. We conducted a cross-ancestry genome-wide association study (GWAS) including 29,612 patients with ALS and 122,656 controls, which identified 15 risk loci. When combined with 8,953 individuals with whole-genome sequencing (6,538 patients, 2,415 controls) and a large cortex-derived expression quantitative trait locus (eQTL) dataset (MetaBrain), analyses revealed locus-specific genetic architectures in which we prioritized genes either through rare variants, short tandem repeats or regulatory effects. ALS-associated risk loci were shared with multiple traits within the neurodegenerative spectrum but with distinct enrichment patterns across brain regions and cell types. Of the environmental and lifestyle risk factors obtained from the literature, Mendelian randomization analyses indicated a causal role for high cholesterol levels. The combination of all ALS-associated signals reveals a role for perturbations in vesicle-mediated transport and autophagy and provides evidence for cell-autonomous disease initiation in glutamatergic neurons.
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| 4. |
- Iacocca, Ezio, 1986, et al.
(författare)
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Spin-current-mediated rapid magnon localisation and coalescence after ultrafast optical pumping of ferrimagnetic alloys
- 2019
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Sub-picosecond magnetisation manipulation via femtosecond optical pumping has attracted wide attention ever since its original discovery in 1996. However, the spatial evolution of the magnetisation is not yet well understood, in part due to the difficulty in experimentally probing such rapid dynamics. Here, we find evidence of a universal rapid magnetic order recovery in ferrimagnets with perpendicular magnetic anisotropy via nonlinear magnon processes. We identify magnon localisation and coalescence processes, whereby localised magnetic textures nucleate and subsequently interact and grow in accordance with a power law formalism. A hydrodynamic representation of the numerical simulations indicates that the appearance of noncollinear magnetisation via optical pumping establishes exchange-mediated spin currents with an equivalent 100% spin polarised charge current density of 10 7 A cm −2 . Such large spin currents precipitate rapid recovery of magnetic order after optical pumping. The magnon processes discussed here provide new insights for the stabilization of desired meta-stable states.
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| 5. |
- Djoussé, L, et al.
(författare)
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Interaction of normal and expanded CAG repeat sizes influences age at onset of Huntington disease.
- 2003
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Ingår i: American Journal of Medical Genetics. Part A. - : Wiley. - 1552-4825 .- 1552-4833. ; 119A:3, s. 279-82
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Tidskriftsartikel (refereegranskat)abstract
- Huntington disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of CAG repeats in the HD gene on chromosome 4p16.3. Past studies have shown that the size of expanded CAG repeat is inversely associated with age at onset (AO) of HD. It is not known whether the normal Huntington allele size influences the relation between the expanded repeat and AO of HD. Data collected from two independent cohorts were used to test the hypothesis that the unexpanded CAG repeat interacts with the expanded CAG repeat to influence AO of HD. In the New England Huntington Disease Center Without Walls (NEHD) cohort of 221 HD affected persons and in the HD-MAPS cohort of 533 HD affected persons, we found evidence supporting an interaction between the expanded and unexpanded CAG repeat sizes which influences AO of HD (P = 0.08 and 0.07, respectively). The association was statistically significant when both cohorts were combined (P = 0.012). The estimated heritability of the AO residual was 0.56 after adjustment for normal and expanded repeats and their interaction. An analysis of tertiles of repeats sizes revealed that the effect of the normal allele is seen among persons with large HD repeat sizes (47-83). These findings suggest that an increase in the size of the normal repeat may mitigate the expression of the disease among HD affected persons with large expanded CAG repeats.
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| 6. |
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| 7. |
- Grånäs, Oscar, 1979-, et al.
(författare)
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Ultrafast modification of the electronic structure of a correlated insulator
- 2022
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Ingår i: Physical Review Research. - : American Physical Society. - 2643-1564. ; 4:3
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Tidskriftsartikel (refereegranskat)abstract
- A nontrivial balance between Coulomb repulsion and kinematic effects determines the electronic structure of correlated electron materials. The use of electromagnetic fields strong enough to rival these native microscopic interactions allows us to study the electronic response as well as the time scales and energies involved in using quantum effects for possible applications. We use element-specific transient x-ray absorption spectroscopy and high-harmonic generation to measure the response to ultrashort off-resonant optical fields in the prototypical correlated electron insulator NiO. Surprisingly, fields of up to 0.22 V/angstrom lead to no detectable changes in the correlated Ni 3d orbitals contrary to previous predictions. A transient directional charge transfer is uncovered, a behavior that is captured by first-principles theory. Our results highlight the importance of retardation effects in electronic screening and pinpoints a key challenge in functionalizing correlated materials for ultrafast device operation.
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| 8. |
- Lutman, A. A., et al.
(författare)
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Polarization control in an X-ray free-electron laser
- 2016
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 10:7, s. 468-472
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Tidskriftsartikel (refereegranskat)abstract
- X-ray free-electron lasers are unique sources of high-brightness coherent radiation. However, existing devices supply only linearly polarized light, precluding studies of chiral dynamics. A device called the Delta undulator has been installed at the Linac Coherent Light Source (LCLS) to provide tunable polarization. With a reverse tapered planar undulator line to pre-microbunch the beam and the novel technique of beam diverting, hundreds of microjoules of circularly polarized X-ray pulses are produced at 500-1,200 eV. These X-ray pulses are tens of femtoseconds long, have a degree of circular polarization of 0.98(+0.02)(-0.04) at 707 eV and may be scanned in energy. We also present a new two-colour X-ray pump-X-ray probe operating mode for the LCLS. Energy differences of Delta E/E = 2.4% are supported, and the second pulse can be adjusted to any elliptical polarization. In this mode, the pointing, timing, intensity and wavelength of the two pulses can be modified.
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| 9. |
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| 10. |
- Gray, A. X., et al.
(författare)
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Ultrafast terahertz field control of electronic and structural interactions in vanadium dioxide
- 2018
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Ingår i: Physical Review B. - : AMER PHYSICAL SOC. - 2469-9950 .- 2469-9969. ; 98:4
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Tidskriftsartikel (refereegranskat)abstract
- Vanadium dioxide (VO2), an archetypal correlated-electron material, undergoes an insulator-metal transition near room temperature that exhibits electron-correlation-driven and structurally driven physics. Using ultrafast temperature- and fluence-dependent optical spectroscopy and x-ray scattering, we show that multiple interrelated electronic and structural processes in the nonequilibrium dynamics in VO2 can be disentangled in the time domain. Specifically, following intense subpicosecond terahertz (THz) electric-field excitation, a partial collapse of the insulating gap occurs within the first picosecond. At temperatures sufficiently close to the transition temperature and for THz peak fields above a threshold of approximately 1 MV/cm, this electronic reconfiguration initiates a change in lattice symmetry taking place on a slower timescale. We identify the kinetic energy increase of electrons tunneling in the strong electric field as the driving force, illustrating a promising method to control electronic and structural interactions in correlated materials on an ultrafast timescale.
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| 11. |
- Henighan, T., et al.
(författare)
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Generation mechanism of terahertz coherent acoustic phonons in Fe
- 2016
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Ingår i: PHYSICAL REVIEW B. - 2469-9950. ; 93:22
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Tidskriftsartikel (refereegranskat)abstract
- We use femtosecond time-resolved hard x-ray scattering to detect coherent acoustic phonons generated during ultrafast laser excitation of ferromagnetic bcc Fe films grown on MgO(001). We observe the coherent longitudinal-acoustic phonons as a function of wave vector through analysis of the temporal oscillations in the x-ray scattering signal. The width of the extracted strain wave front associated with this coherent motion is similar to 100 fs. An effective electronic Gruneisen parameter is extracted within a two-temperature model. However, ab initio calculations show that the phonons are nonthermal on the time scale of the experiment, which calls into question the validity of extracting physical constants by fitting such a two-temperature model.
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| 12. |
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| 13. |
- Chen, Z., et al.
(författare)
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Ultrafast Self-Induced X-Ray Transparency and Loss of Magnetic Diffraction
- 2018
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Ingår i: Physical Review Letters. - : AMER PHYSICAL SOC. - 0031-9007 .- 1079-7114. ; 121:13
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Tidskriftsartikel (refereegranskat)abstract
- Using ultrafast similar or equal to 2.5 fs and similar or equal to 25 fs self-amplified spontaneous emission pulses of increasing intensity and a novel experimental scheme, we report the concurrent increase of stimulated emission in the forward direction and loss of out-of-beam diffraction contrast for a Co/Pd multilayer sample. The experimental results are quantitatively accounted for by a statistical description of the pulses in conjunction with the optical Bloch equations. The dependence of the stimulated sample response on the incident intensity, coherence time, and energy jitter of the employed pulses reveals the importance of increased control of x-ray free electron laser radiation.
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| 14. |
- Kronast, F., et al.
(författare)
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Element-specific magnetic hysteresis of individual 18 nm Fe nanocubes
- 2011
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Ingår i: Nano Letters. - : American Chemical Society (ACS). - 1530-6992 .- 1530-6984. ; 11:4, s. 1710-1715
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Tidskriftsartikel (refereegranskat)abstract
- Correlating the electronic structure and magnetic response with the morphology and crystal structure of the same single ferromagnetic nanoparticle has been up to now an unresolved challenge. Here, we present measurements of the element-specific electronic structure and magnetic response as a function of magnetic field amplitude and orientation for chemically synthesized single Fe nanocubes with 18 nm edge length. Magnetic states and interactions of monomers, dimers, and trimers are analyzed by X-ray photoemission electron microscopy for different particle arrangements. The element-specific electronic structure can be probed and correlated with the changes of magnetic properties. This approach opens new possibilities for a deeper understanding of the collective response of magnetic nanohybrids in multifunctional materials and in nanomagnetic colloidal suspensions used in biomedical and engineering technologies. © 2011 American Chemical Society.
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| 15. |
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| 16. |
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| 17. |
- Terazono, Y., et al.
(författare)
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Photonic control of photoinduced electron transfer via switching of redox potentials in a photochromic moiety
- 2004
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Ingår i: Journal of Physical Chemistry B. ; 108:6, s. 1812-1814
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Tidskriftsartikel (refereegranskat)abstract
- A porphyrin (P) has been covalently linked to a photochromic dihydroindolizine moiety (DHI) to form a P-DHI dyad. When the dihydroindolizine is in its closed, spirocyclic form (DHIc), the photophysics of the attached porphyrin are unaffected. Irradiation with UV light opens the photochromic moiety to the betaine form (DHIo), which has a significantly higher reduction potential than DHIc. Light absorption by the porphyrin moiety of P-DHIo is followed by rapid (50 ps) photoinduced electron transfer to yield the P.+-DHIo(.-) charge-seperated state. This state recombines in 2.9 ps to give the ground state. Irradiation of P-DHIo with light at wavelengths > 590 nm induces photoisomerization back to P-DHIc. Thermal closing can also be achieved. Thus, light is used to switch photoinduced electron transfer on or off. These principles may be useful in the design of molecular optoelectronic devices.
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| 18. |
- Bonetti, Stefano, et al.
(författare)
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Direct observation and imaging of a spin-wave soliton with p−like symmetry
- 2015
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Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- The prediction and realization of magnetic excitations driven by electrical currents via the spin transfer torque effect, enables novel magnetic nano-devices where spin-waves can be used to process and store information. The functional control of such devices relies on understanding the properties of non-linear spin-wave excitations. It has been demonstrated that spin waves can show both an itinerant character, but also appear as localized solitons. So far, it was assumed that localized solitons have essentially cylindrical, s−like symmetry. Using a newly developed high-sensitivity time-resolved magnetic x-ray microscopy, we instead observe the emergence of a novel localized soliton excitation with a nodal line, i.e. with p−like symmetry. Micromagnetic simulations identify the physical mechanism that controls the transition from s− to p−like solitons. Our results suggest a potential new pathway to design artificial atoms with tunable dynamical states using nanoscale magnetic devices.
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| 19. |
- Byrne, L. M., et al.
(författare)
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Neurofilament light protein in blood as a potential biomarker of neurodegeneration in Huntington's disease: a retrospective cohort analysis
- 2017
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Ingår i: Lancet Neurology. - 1474-4422. ; 16:8, s. 601-609
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Tidskriftsartikel (refereegranskat)abstract
- Background Blood biomarkers of neuronal damage could facilitate clinical management of and therapeutic development for Huntington's disease. We investigated whether neurofilament light protein NfL (also known as NF-L) in blood is a potential prognostic marker of neurodegeneration in patients with Huntington's disease. Methods We did a retrospective analysis of healthy controls and carriers of CAG expansion mutations in HTT participating in the 3-year international TRACK-HD study. We studied associations between NfL concentrations in plasma and clinical and MRI neuroimaging findings, namely cognitive function, motor function, and brain volume (global and regional). We used random effects models to analyse cross-sectional associations at each study visit and to assess changes from baseline, with and without adjustment for age and CAG repeat count. In an independent London-based cohort of 37 participants (23 HTT mutation carriers and 14 controls), we further assessed whether concentrations of NfL in plasma correlated with those in CSF. Findings Baseline and follow-up plasma samples were available from 97 controls and 201 individuals carrying HTT mutations. Mean concentrations of NfL in plasma at baseline were significantly higher in HTT mutation carriers than in controls (3.63 [SD 0.54] log pg/mL vs 2.68 [0.52] log pg/mL, p<0.0001) and the difference increased from one disease stage to the next. At any given timepoint, NfL concentrations in plasma correlated with clinical and MRI findings. In longitudinal analyses, baseline NfL concentration in plasma also correlated significantly with subsequent decline in cognition (symbol-digit modality test r=-0.374, p<0.0001; Stroop word reading r=-0.248, p=0.0033), total functional capacity (r=-0.289, p=0.0264), and brain atrophy (caudate r=0.178, p=0.0087; whole-brain r=0602, p<0.0001; grey matter r=0.518, p<00001; white matter r=0.588, p<0.0001; and ventricular expansion r=-0.589, p<0.0001). All changes except Stroop word reading and total functional capacity remained significant after adjustment for age and CAG repeat count. In 104 individuals with premanifest Huntington's disease, NfL concentration in plasma at baseline was associated with subsequent clinical onset during the 3-year follow-up period (hazard ratio 3.29 per log pg/mL, 95% CI 1.48-7.34, p=00036). Concentrations of NfL in CSF and plasma were correlated in mutation carriers (r=0868, p<0.0001). Interpretation NfL in plasma shows promise as a potential prognostic blood biomarker of disease onset and progression in Huntington's disease. Copyright (C) The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license.
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| 20. |
- Creusot, F., et al.
(författare)
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The CIC YAC library: Sizing of the clones and determination of clones carrying repeated DNA sequences.
- 1995
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Ingår i: The Plant Journal. - 0960-7412 .- 1365-313X. ; 8:5, s. 763-770
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Tidskriftsartikel (refereegranskat)abstract
- A new Arabidopsis thaliana (ecotype Columbia) genomic library has been constructed in Yeast Artificial Chromosomes: the CIC library (for CEPH, INRA and CNRS). Optimization of plant culture conditions and protoplast preparation allowed the recovery of large amounts of viable protoplasts. Mechanical shearing of DNA was minimized by isolation of DNA from protoplasts embedded in agarose. Cloning of large inserts was favored by including two successive size fractionation steps (after partial EcoRI digestion and after ligation with the vector arms), which selected DNA fragments larger than 350 kb. The library consists of 1152 clones with an average insert size of 420 kb. Clones carrying chloroplast DNA and various nuclear repeated sequences have been identified. Twenty-one per cent of the clones are found to contain chloroplast DNA. Therefore, the library represents around four nuclear genome equivalents. The clones containing 5S rDNA genes, 18S-25S rDNA sequences and the 180 bp paracentromeric repeated element account for 3.6%, 8.9% and 5.8%, respectively. Only one clone was found to carry the 160 bp paracentromeric repeated element. Given the smaller size of clones carrying Arabidopsis repeated DNA, the average size of remaining clones is around 480 kb. The library was screened by PCR amplification using pairs of primers corresponding to sequences dispersed in the genome. Seventy out of 76 pairs of primers identified from one to seven YAC clones. Thus at least 92% of the genome is represented in the CIC library. The survey of the library for clones containing unlinked DNA sequences indicates that the proportion of chimeric clones is lower than 10%.
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| 21. |
- Djoussé, Luc, et al.
(författare)
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Evidence for a modifier of onset age in Huntington disease linked to the HD gene in 4p16.
- 2004
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Ingår i: Neurogenetics. - : Springer Science and Business Media LLC. - 1364-6745 .- 1364-6753. ; 5:2, s. 109-14
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Tidskriftsartikel (refereegranskat)abstract
- Huntington disease (HD) is a neurodegenerative disorder caused by the abnormal expansion of CAG repeats in the HD gene on chromosome 4p16.3. A recent genome scan for genetic modifiers of age at onset of motor symptoms (AO) in HD suggests that one modifier may reside in the region close to the HD gene itself. We used data from 535 HD participants of the New England Huntington cohort and the HD MAPS cohort to assess whether AO was influenced by any of the three markers in the 4p16 region: MSX1 (Drosophila homeo box homologue 1, formerly known as homeo box 7, HOX7), Delta2642 (within the HD coding sequence), and BJ56 ( D4S127). Suggestive evidence for an association was seen between MSX1 alleles and AO, after adjustment for normal CAG repeat, expanded repeat, and their product term (model P value 0.079). Of the variance of AO that was not accounted for by HD and normal CAG repeats, 0.8% could be attributed to the MSX1 genotype. Individuals with MSX1 genotype 3/3 tended to have younger AO. No association was found between Delta2642 (P=0.44) and BJ56 (P=0.73) and AO. This study supports previous studies suggesting that there may be a significant genetic modifier for AO in HD in the 4p16 region. Furthermore, the modifier may be present on both HD and normal chromosomes bearing the 3 allele of the MSX1 marker.
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| 22. |
- Gasser, T. Christian, et al.
(författare)
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A novel strategy to translate the biomechanical rupture risk of abdominal aortic aneurysms to their equivalent diameter risk : Method and retrospective validation
- 2014
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 47:3, s. 288-295
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To translate the individual abdominal aortic aneurysm (AAA) patient's biomechanical rupture risk profile to risk-equivalent diameters, and to retrospectively test their predictability in ruptured and non-ruptured aneurysms. Methods: Biomechanical parameters of ruptured and non-ruptured AAAs were retrospectively evaluated in a multicenter study. General patient data and high resolution computer tomography angiography (CTA) images from 203 non-ruptured and 40 ruptured aneurysmal infrarenal aortas. Three-dimensional AAA geometries were semi-automatically derived from CTA images. Finite element (FE) models were used to predict peak wall stress (PWS) and peak wall rupture index (PWRI) according to the individual anatomy, gender, blood pressure, intraluminal thrombus (ILT) morphology, and relative aneurysm expansion. Average PWS diameter and PWRI diameter responses were evaluated, which allowed for the PWS equivalent and PWRI equivalent diameters for any individual aneurysm to be defined. Results: PWS increased linearly and PWRI exponentially with respect to maximum AAA diameter. A size-adjusted analysis showed that PWS equivalent and PWRI equivalent diameters were increased by 7.5 mm (p = .013) and 14.0 mm (p < .001) in ruptured cases when compared to non-ruptured controls, respectively. In non-ruptured cases the PWRI equivalent diameters were increased by 13.2 mm (p < .001) in females when compared with males. Conclusions: Biomechanical parameters like PWS and PWRI allow for a highly individualized analysis by integrating factors that influence the risk of AAA rupture like geometry (degree of asymmetry, ILT morphology, etc.) and patient characteristics (gender, family history, blood pressure, etc.). PWRI and the reported annual risk of rupture increase similarly with the diameter. PWRI equivalent diameter expresses the PWRI through the diameter of the average AAA that has the same PWRI, i.e. is at the same biomechanical risk of rupture. Consequently, PWRI equivalent diameter facilitates a straightforward interpretation of biomechanical analysis and connects to diameter-based guidelines for AAA repair indication. PWRI equivalent diameter reflects an additional diagnostic parameter that may provide more accurate clinical data for AAA repair indication.
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| 23. |
- Li, Jian-Liang, et al.
(författare)
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A genome scan for modifiers of age at onset in Huntington disease : The HD MAPS study.
- 2003
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Ingår i: American Journal of Human Genetics. - : Elsevier BV. - 0002-9297 .- 1537-6605. ; 73:3, s. 682-7
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Tidskriftsartikel (refereegranskat)abstract
- Huntington disease (HD) is caused by the expansion of a CAG repeat within the coding region of a novel gene on 4p16.3. Although the variation in age at onset is partly explained by the size of the expanded repeat, the unexplained variation in age at onset is strongly heritable (h2=0.56), which suggests that other genes modify the age at onset of HD. To identify these modifier loci, we performed a 10-cM density genomewide scan in 629 affected sibling pairs (295 pedigrees and 695 individuals), using ages at onset adjusted for the expanded and normal CAG repeat sizes. Because all those studied were HD affected, estimates of allele sharing identical by descent at and around the HD locus were adjusted by a positionally weighted method to correct for the increased allele sharing at 4p. Suggestive evidence for linkage was found at 4p16 (LOD=1.93), 6p21-23 (LOD=2.29), and 6q24-26 (LOD=2.28), which may be useful for investigation of genes that modify age at onset of HD.
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| 24. |
- Mereaux, JL, et al.
(författare)
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Increasing involvement of CAPN1 variants in spastic ataxias and phenotype-genotype correlations
- 2021
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Ingår i: Neurogenetics. - : Springer Science and Business Media LLC. - 1364-6753 .- 1364-6745. ; 22:1, s. 71-79
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Tidskriftsartikel (refereegranskat)abstract
- Spastic ataxias are rare neurogenetic disorders involving spinocerebellar and pyramidal tracts. Many genes are involved. Among them, CAPN1, when mutated, is responsible for a complex inherited form of spastic paraplegia (SPG76). We report the largest published series of 21 novel patients with nine new CAPN1 disease-causing variants and their clinical characteristics from two European university hospitals (Paris and Stockholm). After a formal clinical examination, causative variants were identified by next-generation sequencing and confirmed by Sanger sequencing. CAPN1 variants are a rare cause (~ 1.4%) of young-adult-onset spastic ataxia; however, together with all published cases, they allowed us to better describe the clinical and genetic spectra of this form. Truncating variants are the most frequent, and missense variants lead to earlier age at onset in favor of an additional deleterious effect. Cerebellar ataxia with cerebellar atrophy, dysarthria and lower limb weakness are often associated with spasticity. We also suggest that cognitive impairment and depression should be assessed specifically in the follow-up of SPG76 cases.
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| 25. |
- Reid, A. H., et al.
(författare)
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Beyond a phenomenological description of magnetostriction
- 2018
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Magnetostriction, the strain induced by a change in magnetization, is a universal effect in magnetic materials. Owing to the difficulty in unraveling its microscopic origin, it has been largely treated phenomenologically. Here, we show how the source of magnetostriction-the underlying magnetoelastic stress-can be separated in the time domain, opening the door for an atomistic understanding. X-ray and electron diffraction are used to separate the subpicosecond spin and lattice responses of FePt nanoparticles. Following excitation with a 50-fs laser pulse, time-resolved X-ray diffraction demonstrates that magnetic order is lost within the nanoparticles with a time constant of 146 fs. Ultrafast electron diffraction reveals that this demagnetization is followed by an anisotropic, three-dimensional lattice motion. Analysis of the size, speed, and symmetry of the lattice motion, together with ab initio calculations accounting for the stresses due to electrons and phonons, allow us to reveal the magnetoelastic stress generated by demagnetization.
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| 26. |
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| 27. |
- Zhou Hagström, Nanna, 1993-, et al.
(författare)
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Symmetry-dependent ultrafast manipulation of nanoscale magnetic domains
- 2022
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 106:22
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Tidskriftsartikel (refereegranskat)abstract
- Femtosecond optical pumping of magnetic materials has been used to achieve ultrafast switching and recently to nucleate symmetry-broken magnetic states. However, when the magnetic order parameter already presents a broken-symmetry state, such as a domain pattern, the dynamics are poorly understood and consensus remains elusive. Here, we resolve the controversies in the literature by studying the ultrafast response of magnetic domain patterns with varying degrees of translation symmetry with ultrafast x-ray resonant scattering. A data analysis technique is introduced to disentangle the isotropic and anisotropic components of the x-ray scattering. We find that the scattered intensity exhibits a radial shift restricted to the isotropic component, indicating that the far-from-equilibrium magnetization dynamics are intrinsically related to the spatial features of the domain pattern. Our results suggest alternative pathways for the spatiotemporal manipulation of magnetism via far-from-equilibrium dynamics and by carefully tuning the ground-state magnetic textures.
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| 28. |
- Zusin, Dmitriy, et al.
(författare)
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Ultrafast perturbation of magnetic domains by optical pumping in a ferromagnetic multilayer
- 2022
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 106:14
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Tidskriftsartikel (refereegranskat)abstract
- Ultrafast optical pumping of spatially nonuniform magnetic textures is known to induce far-from-equilibrium spin transport effects. Here, we use ultrafast x-ray diffraction with unprecedented dynamic range to study the laser-induced dynamics of labyrinth domain networks in ferromagnetic CoFe/Ni multilayers. We detected azimuthally isotropic, odd order, magnetic diffraction rings up to fifth order. The amplitudes of all three diffraction rings quench to different degrees within 1.6 ps. In addition, all three of the detected diffraction rings both broaden by 15% and radially contract by 6% during the quench process. We are able to rigorously quantify a 31% ultrafast broadening of the domain walls via Fourier analysis of the order-dependent quenching of the three detected diffraction rings. The broadening of the diffraction rings is interpreted as a reduction in the domain coherence length, but the shift in the ring radius, while unambiguous in its occurrence, remains unexplained. In particular, we demonstrate that a radial shift explained by domain-wall broadening can be ruled out. With the unprecedented dynamic range of our data, our results provide convincing evidence that labyrinth domain structures are spatially perturbed at ultrafast speeds under far-from-equilibrium conditions, albeit the mechanism inducing the perturbations remains yet to be clarified.
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| 29. |
- Bonetti, Stefano, et al.
(författare)
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THz-Driven Ultrafast Spin-Lattice Scattering in Amorphous Metallic Ferromagnets
- 2016
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Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 117:8
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Tidskriftsartikel (refereegranskat)abstract
- We use single-cycle THz fields and the femtosecond magneto-optical Kerr effect to, respectively, excite and probe the magnetization dynamics in two thin-film ferromagnets with different lattice structures: crystalline Fe and amorphous CoFeB. We observe Landau-Lifshitz-torque magnetization dynamics of comparable magnitude in both systems, but only the amorphous sample shows ultrafast demagnetization caused by the spin-lattice depolarization of the THz-induced ultrafast spin current. Quantitative modeling shows that such spin-lattice scattering events occur on similar time scales than the conventional spin conserving electronic scattering (similar to 30 fs). This is significantly faster than optical laser-induced demagnetization. THz conductivity measurements point towards the influence of lattice disorder in amorphous CoFeB as the driving force for enhanced spin-lattice scattering.
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| 30. |
- Borglin, Johan, 1986, et al.
(författare)
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Annular Beam Shaping in Multiphoton Microscopy to Reduce Out-of-Focus Background
- 2017
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Ingår i: International Journal of Spectroscopy. - : Hindawi Limited. - 1687-9449 .- 1687-9457.
-
Tidskriftsartikel (refereegranskat)abstract
- Despite the inherent spatial confinement of multiphoton processes that arises from focusing through an objective, the maximum imaging depth in conventional multiphoton microscopy is ultimately limited by noise from out-of-focus fluorescence. This is particularly evident when imaging beyond shallow depths in highly scattering tissue as increased laser powers are necessary. The out-of-focus signal originates from multiphoton processes taking place primarily at shallow depths and deteriorates contrast and limits imaging depth. In this paper, annular laser beams are explored as a concept to reduce this background signal in multiphoton microscopy. The approach is theoretically verified by data from simulations and proof of principle is demonstrated on a custom-built experimental multiphoton microscopy platform. Annular laser beams were created by adopting wavefront control using a spatial light modulator and implemented for imaging tissue phantoms simulating turbid media and human skin ex vivo. The signal-to-background ratios were calculated and compared to images acquired with a traditional, filled-aperture Gaussian beam. Experiments in tissue phantom show an improvement in signal-to-background ratio of about 30% when using annular beam illumination in comparison to Gaussian illumination at specific depths. When laser power is not the limiting factor, this approach is expected to provide even greater benefits.
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| 31. |
- Borglin, Johan, 1986, et al.
(författare)
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Improving multiphoton microscopy using annular beam shaping, focusing on imaging of human skin
- 2014
-
Ingår i: Multiphoton Microscopy in the Biomedical Sciences XIV: 2-4 February 2014, San Francisco, California, United States. Progress in Biomedical Optics and Imaging - Proceedings of SPIE. - : SPIE. - 1605-7422. ; 8948
-
Konferensbidrag (refereegranskat)abstract
- Multiphoton fluorescence microscopy (MPM) is a method for high resolution, non-invasive investigations of biological tissue. The aim of introducing an annular shaped laser beam is to reduce the ouf-of-focus generated background signal improving imaging of light scattering tissue such as human skin. Simulations show that 50% of the beam radius can be blocked, while preserving the shape of the point spread function. Initial experiments performed on a phantom consisting of fluorescein and fluorescent beads embedded in agar by using a custom built MPM-set up show that by introducing a simple beam blocker to create an annular beam, the background signal is reduced with approximately 5%. Future work will include optimizing the set up, and creating phantoms with more light scattering properties. © 2014 SPIE.
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| 32. |
- Chi, Gamma, et al.
(författare)
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Cryo-EM structure of the human Kv3.1 channel reveals gating control by the cytoplasmic T1 domain
- 2022
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13:1
-
Tidskriftsartikel (refereegranskat)abstract
- Kv3 channels have distinctive gating kinetics tailored for rapid repolarization in fast-spiking neurons. Malfunction of this process due to genetic variants in the KCNC1 gene causes severe epileptic disorders, yet the structural determinants for the unusual gating properties remain elusive. Here, we present cryo-electron microscopy structures of the human Kv3.1a channel, revealing a unique arrangement of the cytoplasmic tetramerization domain T1 which facilitates interactions with C-terminal axonal targeting motif and key components of the gating machinery. Additional interactions between S1/S2 linker and turret domain strengthen the interface between voltage sensor and pore domain. Supported by molecular dynamics simulations, electrophysiological and mutational analyses, we identify several residues in the S4/S5 linker which influence the gating kinetics and an electrostatic interaction between acidic residues in alpha 6 of T1 and R449 in the pore-flanking S6T helices. These findings provide insights into gating control and disease mechanisms and may guide strategies for the design of pharmaceutical drugs targeting Kv3 channels. Here, Chi et al. report cryo-EM structures of the human Kv3.1a channel, revealing a unique arrangement of the cytoplasmic T1 domain, which allows the interactions with the C-terminal axonal targeting motif and key components of the gating machinery. These findings provide insights into the functional relevance of previously unknown interdomain interactions in Kv3 channels and may guide the design of new pharmaceutical drugs.
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| 33. |
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| 34. |
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| 35. |
- Durr, Hermann A., et al.
(författare)
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A Closer Look Into Magnetism : Opportunities With Synchrotron Radiation
- 2009
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Ingår i: IEEE transactions on magnetics. - 0018-9464 .- 1941-0069. ; 45:1, s. 15-57
-
Forskningsöversikt (refereegranskat)abstract
- The unique properties of synchrotron radiation, such as broad energy spectrum, variable light polarization, and flexible time structure, have made it an enormously powerful tool in the study of magnetic phenomena and materials. The refinement of experimental techniques has led to many new research opportunities, keeping up with the challenges put up by modern magnetism research. In this contribution, we review some of the recent developments in the application of synchrotron radiation and particularly soft X-rays to current problems in magnetism, and we discuss future perspectives.
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| 36. |
- Dürr, Hermann A., et al.
(författare)
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Revealing momentum-dependent electron-phonon and phonon-phonon coupling in complex materials with ultrafast electron diffuse scattering
- 2021
-
Ingår i: MRS bulletin. - : Springer Nature. - 0883-7694 .- 1938-1425. ; 46:8, s. 731-737
-
Tidskriftsartikel (refereegranskat)abstract
- Despite their fundamental role in determining many important properties of materials, detailed momentum-dependent information on the strength of electron–phonon and phonon–phonon coupling across the entire Brillouin zone has remained elusive. Ultrafast electron diffuse scattering (UEDS) is a recently developed technique that is making a significant contribution to these questions. Here, we describe both the UEDS methodology and the information content of ultrafast, photoinduced changes in phonon-diffuse scattering from single-crystal materials. We present results obtained from Ni, WSe2, and TiSe2, materials that are characterized by a complex interplay between electronic (charge, spin) and lattice degrees of freedom. We demonstrate the power of this technique by unraveling carrier–phonon and phonon–phonon interactions in both momentum and time and following nonequilibrium phonon dynamics in detail on ultrafast time scales. By combining ab initio calculations with ultrafast diffuse electron scattering, insights into electronic and magnetic dynamics that impact UEDS indirectly can also be obtained.
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| 37. |
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| 38. |
- Erhart, P., et al.
(författare)
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Finite Element Analysis in Asymptomatic, Symptomatic, and Ruptured Abdominal Aortic Aneurysms : In Search of New Rupture Risk Predictors
- 2015
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier BV. - 1078-5884 .- 1532-2165. ; 49:3, s. 239-245
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives: To compare biomechanical rupture risk parameters of asymptomatic, symptomatic and ruptured abdominal aortic aneurysms (AAA) using finite element analysis (FEA). Study design: Retrospective biomechanical single center analysis of asymptomatic, symptomatic, and ruptured AAAs. Comparison of biomechanical parameters from FEA. Materials and methods: From 2011 to 2013 computed tomography angiography (CTA) data from 30 asymptomatic, 15 symptomatic, and 15 ruptured AAAs were collected consecutively. FEA was performed according to the successive steps of AAA vessel reconstruction, segmentation and finite element computation. Biomechanical parameters Peak Wall Rupture Risk Index (PWRI), Peak Wall Stress (PWS), and Rupture Risk Equivalent Diameter (RRED) were compared among the three subgroups. Results: PWRI differentiated between asymptomatic and symptomatic AAAs (p < .0004) better than PWS (p < .1453). PWRI-dependent RRED was higher in the symptomatic subgroup compared with the asymptomatic subgroup (p < .0004). Maximum AAA external diameters were comparable between the two groups (p < .1355). Ruptured AAAs showed the highest values for external diameter, total intraluminal thrombus volume, PWS, RRED, and PWRI compared with asymptomatic and symptomatic AAAs. In contrast with symptomatic and ruptured AAAs, none of the asymptomatic patients had a PWRI value >1.0. This threshold value might identify patients at imminent risk of rupture: Conclusions: From different FEA derived parameter, PWRI distinguishes most precisely between asymptomatic and symptomatic AAAs. If elevated, this value may represent a negative prognostic factor for asymptomatic AAAs.
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| 39. |
- Erhart, P., et al.
(författare)
-
Finite-Elemente-Analyse abdomineller Aortenaneurysmen : Aktuelle Wertigkeit als Ergänzung zur herkömmlichen Diagnostik
- 2015
-
Ingår i: Gefässchirurgie. - : Springer Science and Business Media LLC. - 0948-7034 .- 1434-3932. ; 20:7, s. 503-507
-
Tidskriftsartikel (refereegranskat)abstract
- Finite element analysis (FEA) of abdominal aortic aneurysms (AAA) could enable a more precise patient-specific risk assessment of AAA rupture. Further clinical studies are needed to validate this model as a clinical decision-making tool. The A4clinics™ software provides a simple and detailed FEA simulation. After implementation of a FEA workstation in a high volume university vascular center, relevant studies for further model validation are expected to be carried out.
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| 40. |
- Erhart, P, et al.
(författare)
-
Prediction of Rupture Sites in Abdominal Aortic Aneurysms After Finite Element Analysis
- 2016
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Ingår i: Journal of endovascular therapy : an official journal of the International Society of Endovascular Specialists. - : SAGE Publications. - 1545-1550. ; 23:1, s. 115-120
-
Tidskriftsartikel (refereegranskat)abstract
- Purpose: To associate regions of highest local rupture risk from finite element analysis (FEA) to subsequent rupture sites in abdominal aortic aneurysms (AAA). Methods: This retrospective multicenter study analyzed computed tomography angiography (CTA) data from 13 asymptomatic AAA patients (mean age 76 years; 8 men) experiencing rupture at a later point in time between 2005 and 2011. All patients had CTA scans before and during the rupture event. FEA was performed to calculate peak wall stress (PWS), peak wall rupture risk (PWRR), rupture risk equivalent diameters (RRED), and the intraluminal thrombus volume (ILTV). PWS and PWRR locations in the prerupture state were compared with subsequent CTA rupture findings. Visible contrast extravasation was considered a definite (n=5) rupture sign, while a periaortic hematoma was an indefinite (n=8) sign. A statistical comparison was performed between the 13-patient asymptomatic AAA group before and during rupture and a 23-patient diameter-matched asymptomatic AAA control group that underwent elective surgery. Results: The asymptomatic AAAs before rupture showed significantly higher PWRR and RRED values compared to the matched asymptomatic AAA control group (median values 0.74 vs 0.52 and 77 vs 59 mm, respectively; p<0.0001 for both). No statistical differences could be found for PWS and ILTV. Ruptured AAAs showed the highest maximum diameters, PWRR, and RRED values. In 7 of the ruptured AAAs (2 definite and 5 indefinite rupture signs), CTA rupture sites correlated with prerupture PWRR locations. Conclusion: The location of the PWRR in unruptured AAAs predicted future rupture sites in several cases. Asymptomatic AAA patients with high PWRR and RRED values have an increased rupture risk.
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| 41. |
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| 42. |
- Higley, Daniel J., et al.
(författare)
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Femtosecond X-ray induced changes of the electronic and magnetic response of solids from electron redistribution
- 2019
-
Ingår i: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Resonant X-ray absorption, where an X-ray photon excites a core electron into an unoccupied valence state, is an essential process in many standard X-ray spectroscopies. With increasing X-ray intensity, the X-ray absorption strength is expected to become nonlinear. Here, we report the onset of such a nonlinearity in the resonant X-ray absorption of magnetic Co/Pd multilayers near the Co L-3 edge. The nonlinearity is directly observed through the change of the absorption spectrum, which is modified in less than 40 fs within 2 eV of its threshold. This is interpreted as a redistribution of valence electrons near the Fermi level. For our magnetic sample this also involves mixing of majority and minority spins, due to sample demagnetization. Our findings reveal that nonlinear X-ray responses of materials may already occur at relatively low intensities, where the macroscopic sample is not destroyed, providing insight into ultrafast charge and spin dynamics.
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| 43. |
- Hyhlik-Dürr, A., et al.
(författare)
-
Finite Element Analysis of Abdominal Aortic Aneurysms : Preliminary Results of Intra and Inter observer Validation
- 2010
-
Konferensbidrag (refereegranskat)abstract
- Objective: Treatment of abdominal aortic aneurysm (AAA) is indicated if risk for rupture exceeds the risk for aortic repair. Estimation of the individual risk for rupture in AAA is therefore essential. The diameter of AAA is known as an independent risk factor for rupture and therefore the base of indication for surgical or endovascular therapy. For more sensitive patient selection, other morphological or hemodynamic predictors such as volume or peak wall stress have to be evaluated. The purpose of this study was to analyze the reproducibility of diameter measurement, volume estimation and peak wall stress calculation in AAA by finite element analysis. Methods: Computed tomography angiography (CTA) scans of 10 patients with AAA and 4 volunteers with healthy infrarenal aortas were analyzed by three independent investigators. A semiautomatic reconstruction using two- and three-dimensional deformable (active) contour models was used to segment vascular bodies from CTA data. Centreline calculated maximal diameter and volume measurements, as extracted from the reconstructed abdominal aorta, as well as peak wall stress, as predicted by three-dimensional non-linear finite element models, were analyzed. Specifically, aortic wall and thrombus tissue were captured by isotropic, non-linear and finite strain constitutive models. Likewise, mean arterial pressure was applied at the luminal surface, the vessels were fixed at the renal arteries and the aortic bifurcation and no contact with surrounding organs was considered. Inter- and intra-observer variabilities for diameter, volume and peak wall stress measurements were assessed by calculating the coefficient of variation (CV=SD*100/mean in %) of the five fold determinations. The methodological variation was expressed as deviation of diameter (mm), volume (ml) and peak wall stress (kPa) amongst the three observers. Results: Reproducibility measurements in healthy vessels of aortic diameters between 16.1mm to 16.6mm varied from CV=2.5% to CV=4.9%. Abdominal aortic volumes of 14ml to 15ml were measured in the healthy cohort with a reproducibility of CV=5.8% to CV=11.5%. Peak wall stress varied between 53 kPa and 55 kPa, where CV ranged from 3-13%. Inter-observer variation was <10% for diameter, volume and peak stress in healthy volunteers. Aortic diameter in three AAAs was measured to 58.9 mm; 54.6 mm; and 71.2 mm respectively. The coefficient of variation showed high agreement with values less than 5%. AAA volume varied between 130 ml and 300 ml (CV < 10%) and Peak wall stress was predicted between 172 kPa and 296 kPa (CV <10%). Variability between the 3 observers in AAA measurements was 0.7 mm – 6.0 mm for diameter, 11 – 28 ml for volume and 4-27 kPa for peak wall stress, respectively. Conclusions: Volume and diameter measurements based on geometrical models reconstructed from CTA scans showed quit good reproducibility for serial measurements in normal and degenerative arteries. Peak wall stress predictions exhibited high accordance between different observers, and in serial measurements within one observer. Volume and peak wall stress analysis could be an additionally module for assessment of individual rupture risk in AAA in the future, which however needs to be validated by additional studies.
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| 44. |
- Hyhlik-Dürr, A., et al.
(författare)
-
Finite-Elemente-Analyse abdomineller Aortenaneurysmen : Erste Ergebnisse der Intra- und Interobserver Validierung
- 2010
-
Konferensbidrag (refereegranskat)abstract
- Hintergrund: Die Therapie des abdominellen Aortenaneurysmas (AAA) ist indiziert, wenn das Rupturrisiko das Risiko der elektiven Operation übersteigt. Die Abschätzung des individuellen Rupturrisikos gilt als Basis der Indikationsstellung zur offenen oder endovaskulären Chirurgie. Bisher wird der Durchmesser des AAA als maßgeblicher Risikofaktor für die Ruptur herangezogen. Für eine sensitivere Indikationsstellung sollten jedoch andere morphologische oder biomechanische Faktoren wie die Volumenveränderung im Verlauf und/oder die Wandspannung im Aneurysma untersucht werden. Ziel dieser Studie ist die Analyse der Reproduzierbarkeit der Durchmesserbestimmung sowie der Volumen- und Wandspannungsberechnung anhand eines geometrischen Modells, basierend auf der Finite Elemente Methode. Methode: Computertomographische Daten von vier gesunden und zehn Patienten mit infrarenalen abdominellen Aneurysmen werden von drei unabhängigen Untersuchern analysiert. Die abdominelle Aorta wird semiautomatisch von Computertomographie-Angiographie (CTA) Bilddaten segmentiert, wobei zwei und drei-dimensionale aktive Konturmodelle, wie sie aus der Bildverarbeitung bekannt sind, zum Einsatz kommen. Der maximale Durchmesser (cernterline-basiert) sowie das aortale Volumen werden aus den rekonstruierten dreidimensionalen Modellen berechnet. Zusätzlich werden nicht-lineare Finite Elemente Modelle verwendet, um die mechanische Spannung in der Aortenwand zwischen der Aortenbifurkation und den Nierenarterien zu bestimmen. Zu diesen Zweck wird der mittlere arterielle Druck als Belastung angenommen und nicht-lineare isotrope Materialmodelle erfassen die mechanischen Eigenschaften der Aortenwand und des Thrombusgewebes. Die Intra- und Interobserver Variabilität der fünf Messungen des maximalen Durchmessers, des Volumens und der maximalen Wandspannung wurden durch die Berechnung des Variationskoeffizienten (CV=SD*100/Arithmethisches Mittel in %) ausgedrückt. Die methodische Variation berechnet sich aus der Abweichung des Duchmessers (mm), des Volumens (ml) und der maximalen Wandspannung (kPA) zwischen den drei Untersuchern. Ergebnisse: Die Reproduzierbarkeit gesunder Gefäßen lag bei einem Durchmesser zwischen 16.1mm und 16.6mm zwischen CV=2,5% und CV=4,9%. Das aortale Volumen lag zwischen 14ml und 15ml, die Reproduzierbarkeit bei den gesunden Gefäßen streute zwischen CV=5.8% und CV=11.5%. Die maximale Wandspannung variierte zwischen 53 kPA and 55 kPa, der CV% lag hierbei zwischen 3 und 13. Die Interobserver Variabilität lag < 10% für den Durchmesser, die Volumenbestimmung und die Bestimmung der maximale Wandspannung. Der maximale Durchmesser der Aorta bei 3 Patienten mit infrarenalem Aneurysma wurde mit durchschnittlich 58.9mm, 54.6mm und 71.2mm berechnet (Stand bei Abstracteinreichung). Der Variationskoeffizient zeigte dabei eine hohe Übereinstimmung mit Werten unter 5%. Das Volumen der Aneurysmen schwankte zwischen 130 ml und 300 ml (CV<10%), die berechnete Wandspannung lag zwischen 172 kPA und 296 kPA (CV<10%). Die Variabilität zwischen den drei Untersuchern betrug 0,7-6,0 mm für den Durchmesser, 11-28 ml für das Volumen und 4-27 kPA für die maximale Wandspannung. Zusammenfassung: Sowohl an gesunden als auch an degenerativ veränderten Gefäßen ergibt die Reproduzierbarkeit des Aortendurchmessers und des aortalen Volumens basierend auf dem dreidimensionalen rekonstruierten Modellen eine hohe Übereinstimmung. Die berechnete Wandspannung basierend auf den Finiten Elemente Modellen zeigt einen geringen Grad an Variabilität sowohl zwischen verschiedenen Untersuchern als auch bei wiederholter Messung. Daher könnten die Volumenbestimmung und die Analyse der Wandspannung zusätzliche Größen bei der Bestimmung des individuellen Rupturrisikos bei Patienten mit Aortenaneurysmen darstellen, um eine präzisere Indikationsstellung zu ermöglichen.
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| 45. |
- Johnson, Eileanoir B, et al.
(författare)
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Neurofilament light protein in blood predicts regional atrophy in Huntington disease.
- 2018
-
Ingår i: Neurology. - 1526-632X. ; 90:8
-
Tidskriftsartikel (refereegranskat)abstract
- Neurofilament light (NfL) protein in blood plasma has been proposed as a prognostic biomarker of neurodegeneration in a number of conditions, including Huntington disease (HD). This study investigates the regional distribution of NfL-associated neural pathology in HD gene expansion carriers.We examined associations between NfL measured in plasma and regionally specific atrophy in cross-sectional (n = 198) and longitudinal (n = 177) data in HD gene expansion carriers from the international multisite TRACK-HD study. Using voxel-based morphometry, we measured associations between baseline NfL levels and both baseline gray matter and white matter volume; and longitudinal change in gray matter and white matter over the subsequent 3 years in HD gene expansion carriers.After controlling for demographics, associations between increased NfL levels and reduced brain volume were seen in cortical and subcortical gray matter and within the white matter. After also controlling for known predictors of disease progression (age and CAG repeat length), associations were limited to the caudate and putamen. Longitudinally, NfL predicted subsequent occipital gray matter atrophy and widespread white matter reduction, both before and after correction for other predictors of disease progression.These findings highlight the value of NfL as a dynamic marker of brain atrophy and, more generally, provide further evidence of the strong association between plasma NfL level, a candidate blood biomarker, and pathologic neuronal change.
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| 46. |
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| 47. |
- Laruelle, G. G., et al.
(författare)
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Anthropogenic perturbations of the silicon cycle at the global scale: Key role of the land-ocean transition
- 2009
-
Ingår i: Global Biogeochemical Cycles. - 0886-6236 .- 1944-9224. ; 23
-
Forskningsöversikt (refereegranskat)abstract
- Silicon (Si), in the form of dissolved silicate (DSi), is a key nutrient in marine and continental ecosystems. DSi is taken up by organisms to produce structural elements (e.g., shells and phytoliths) composed of amorphous biogenic silica (bSiO(2)). A global mass balance model of the biologically active part of the modern Si cycle is derived on the basis of a systematic review of existing data regarding terrestrial and oceanic production fluxes, reservoir sizes, and residence times for DSi and bSiO(2). The model demonstrates the high sensitivity of biogeochemical Si cycling in the coastal zone to anthropogenic pressures, such as river damming and global temperature rise. As a result, further significant changes in the production and recycling of bSiO(2) in the coastal zone are to be expected over the course of this century.
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| 48. |
- Le Guyader, Loïc, et al.
(författare)
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State-resolved ultrafast charge and spin dynamics in [Co/Pd] multilayers
- 2022
-
Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 120:3
-
Tidskriftsartikel (refereegranskat)abstract
- We use transient absorption spectroscopy with circularly polarized x rays to detect laser-excited hole states below the Fermi level and compare their dynamics with that of unoccupied states above the Fermi level in ferromagnetic [Co/Pd] multilayers. While below the Fermi level, an instantaneous and significantly stronger demagnetization is observed, above the Fermi level, the demagnetization is delayed by 35 ± 10 fs. This provides a direct visualization of how ultrafast demagnetization proceeds via initial spin-flip scattering of laser-excited holes to the subsequent formation of spin waves.
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| 49. |
- Le, Phu Tran Phong, et al.
(författare)
-
Tailoring Vanadium Dioxide Film Orientation Using Nanosheets : a Combined Microscopy, Diffraction, Transport, and Soft X-Ray in Transmission Study
- 2020
-
Ingår i: Advanced Functional Materials. - : WILEY-V C H VERLAG GMBH. - 1616-301X .- 1616-3028. ; 30:1
-
Tidskriftsartikel (refereegranskat)abstract
- Vanadium dioxide (VO2) is a much-discussed material for oxide electronics and neuromorphic computing applications. Here, heteroepitaxy of VO2 is realized on top of oxide nanosheets that cover either the amorphous silicon dioxide surfaces of Si substrates or X-ray transparent silicon nitride membranes. The out-of-plane orientation of the VO2 thin films is controlled at will between (011)(M1)/(110)(R) and (-402)(M1)/(002)(R) by coating the bulk substrates with Ti0.87O2 and NbWO6 nanosheets, respectively, prior to VO2 growth. Temperature-dependent X-ray diffraction and automated crystal orientation mapping in microprobe transmission electron microscope mode (ACOM-TEM) characterize the high phase purity, the crystallographic and orientational properties of the VO2 films. Transport measurements and soft X-ray absorption in transmission are used to probe the VO2 metal-insulator transition, showing results of a quality equal to those from epitaxial films on bulk single-crystal substrates. Successful local manipulation of two different VO2 orientations on a single substrate is demonstrated using VO2 grown on lithographically patterned lines of Ti0.87O2 and NbWO6 nanosheets investigated by electron backscatter diffraction. Finally, the excellent suitability of these nanosheet-templated VO2 films for advanced lensless imaging of the metal-insulator transition using coherent soft X-rays is discussed.
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| 50. |
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